Mathematics
: asked on ca1137b137e61e77e0296e89d6d02c8f

06.04.2020

need help with questions 11-14 please

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16.02.2023, solved by verified expert

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**Answer:**

**Step-by-step explanation:**

11)

7/9 = b/b - 10

Cross multiplying,

7(b - 10) = 9b

7b - 70 = 9b

Adding 70 to both sides,

7b = 9b + 70

Subtracting 9b from both sides,

-2b = 70

Diving both sides by -2,

**b = -35**

12)

9/k - 7 = 6/k

Cross multiplying,

9k = 6(k - 7)

9k = 6k - 42

Subtracting 6k from both sides,

3k = -42

Dividing both sides by 3,

**k = -14**

13)

Using similarity of triangles property,

(3x - 5)/(3x - 5 + 10) = (28 - 8)/28

(3x - 5)/(3x + 5) = 5/7

Cross multiplying,

7(3x - 5) = 5(3x + 5)

21x - 35 = 15x + 25

Subtracting 15x from both sides,

6x - 35 = 25

Adding 35 to both sides,

6x = 60

Dividing both sides by 6,

**x = 10**

14)

Using similarity of triangles property,

16/(16 + 6) = x/(x + 9)

8/11 = x/(x + 9)

Cross multiplying,

8(x + 9) = 11x

8x + 72 = 11x

Subtracting 8x from both sides,

72 = 3x

Dividing both sides by 3,

**x = 24**

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